Lawrence Berkeley National Laboratory

Cooking is a major source of indoor air pollution, making high-efficiency ventilation systems essential for containing cooking pollutants. This study proposes a novel push-pull ventilation system with an inclined capture jet at the side edge of the stove. Particle image velocimetry and the scattering grayscale method were used to measure airflow characteristics and particle concentration distributions in the cooking zone under different exhaust flowrates, capture jet velocities, and simulated cooking operation disturbances. The results show that the capture jet gradually dominates the cooking zone airflow with increasing velocity, and its centerline aligns with the exhaust outlet, forming a stable containment zone. The deflection angle of the capture jet under heating conditions is larger than that under isothermal conditions. The deflection angle increases with the exhaust flowrate and decreases with the jet velocity. Empirical linear models for jet centerline trajectory and velocity decay can accurately describe these relationships. Cooking operation disturbances increase the thermal plume radius and the capture jet entrainment radius but have negligible impacts on the jet deflection angle at 0.8 m/s. The capture jet effectively reduces high-turbulence zones and enhances pollutant containment. Cooking operation disturbances reduce total particle capture efficiency (CE) by up to 5%, and this reduction increases with disturbance speed. The ventilation system exhibits optimal containment and capture performance at a jet velocity of 0.8 m/s, achieving total CEs of 95.9%–97.1% at exhaust flow rates of 360–480 m³/h. Compared to corresponding cases without the capture jet, the new system improves total CE by up to 14%.